Comparison of fracture resistance of implant supported fixed prothesis substructure materials with different cross-sectional geometry

Background The aim of this study was to compare fracture resistance after thermomechanical ageing of prosthetic substructure materials with different connector designs. Methods Three different prosthetic substructure materials were used in this study: (1) GroupZir: ( Zirconia, Fusion ceram,Turkey), (2)GroupPEEK (PEEK, Whitepeaks, CopraPeek, Essen, Germany), (3)GroupFRC (Fibre-reinforced composite, Trinia, Bicon Implant, Rep. of Ireland). A total of 72 implant-supported prosthesis triangular, square, and oval connector designs were created between 2nd premolar and mandibular 2nd molar teeth. After adhesion to the implant abutments with resin cement (Pentron breeze, Kerr), the samples were applied with dynamic loading and thermomechanical ageing (120,000 cycles,120 N,5–55°C). Fracture resistance values were obtained with a universal test device and SEM images were analysed. The analyses were performed with Two-Way ANOVA and the Tukey test (SPSS 23.00). Results Both the material and the connector type were found to affect the fracture resistance (F = 8.354, p < 0.05). The highest fracture resistance value was obtained from the triangular shape in GroupZir(3200 ± 91.05) and the lowest from the oval connector design of GroupPEEK material (2410 ± 157.23). Statistically significant differences were determined in the different connector designs of GroupZir(p < 0.05). In the comparisons made according to connector design, a significant difference was obtained between GroupZir and GroupPEEK and between GroupZir and GroupFRC. Deformations were observed in the fracture pattern of the Group Zir samples and deformations in the form of rupture were seen in the GroupPEEK and GroupFRC material samples. Conclusions The study results demonstrated that the fracture resistance of zirconia, PEEK, and FRC restorations over 3-unit implants with different connectors is affected by connector design. All the materials were seen to be comparable in respect of the forces formed in chewing dynamics.